Winegard YA-1713 is a 10-element, Hi-VHF Band (Ch7-13) hybrid Log-Yagi. Fol. results are for measurements from LATEST MODEL. Third and second elements form a two-element Log Periodic Array "Cell" surrounded by a Yagi-type Reflector and seven Directors.
The Crossover Transmission Feedline between third and second elements is investigated to find the optimum simulation parameters. In 4nec2, the TL Card stipulates the characteristic impedance (Zc) and length (Lc). When Lc=0, a direct connection line is assumed.
UPDATE (21Jan2009): Reran everything using latest 4nec2 version and final, very minor, tweaks to holl_ands measurements. Very little change wrt earlier posting. Added Summary Charts.
Ken Nist's w1713a.ez file stipulated Lc equal to the distance between Element #2 and #3, equivalent to a direct connection, rather than simulating how the feedline snakes around the boom, thereby changing the phase of the signal to Element#2.
Two SOURCE options were investigated: Element#3 and Balun Feed (Slide #19 onward), emulating the Balun location under Element #4, being connected to Element#3 via another non-crossing transmission line (Zb, Lb).
SOURCE at 1:1 75-ohm Balun location had best Net Gain and lowest SWR (whether 75 or 300-ohm Balun). LD1 Card emulated 50-pF Capacitor across Balun, but only resulted in a few tenths of a dB reduction in Gain Loss on Ch13.
EDIT (18Sept2010): Added Elevation Angle Gain Charts.
Date(s): 21 Jan 2009 UPDATE. Album by holl_ands. 1 - 58 of 58 Total. 2953 Visits.
enlarge 0KB, 1024x683 1 holl_ands YA-1713 Results Comparison - Raw Gain
Even more Gain Loss across Ch13 than Ken Nist's Chart posted on hdtvprimer.
HOWEVER, two On-Air Tests found NO LOSS across Ch13. (Back up to YA-1713 Summary Page for References]
enlarge 0KB, 1024x683 2 holl_ands YA-1713 Results Comparison - Net Gain Even more Gain Loss across Ch13 than hdtvprimer.
enlarge 0KB, 1024x458 34 Geometry View showing SOURCE at simulated Balun Feed location under, but not connected to Element #4.
Second TL Card has parameters for Characteristic Impedance (Zb) and Balun Feed Length (Lb).
enlarge 0KB, 1024x819 35 YA-1713 with SOURCE at Balun Location Sweep Lt at 213 MHz. Initially tried Zb=Zc=75-ohm.
Shorter Lt slightly improves Gain and F/B but further degrades SWR.
enlarge 0KB, 1024x819 36 YA-1713 with SOURCE at Balun Location Sweep Zb at 213 MHz. Initially tried Zc=75-ohm.
Gain and F/B are unaffected. Minimum SWR at Zc=75-ohm.
enlarge 0KB, 1024x819 37 YA-1713 with SOURCE at Balun Location Sweep Zc at 213 MHz. Initially tried Zb=75-ohm.
Gain and F/B are mildly affected. Minimum SWR at Zc=175-ohm.
enlarge 0KB, 1024x819 38 YA-1713 with SOURCE at Balun Location Sweep Zb at 213 MHz. For optimized Zc=225-ohm.
Gain and F/B are unaffected. Minimum SWR at Zc=150-ohm.
enlarge 0KB, 1024x819 39 YA-1713 with SOURCE at Balun Location. Sweep Lt at 213 MHz. For Optimized Zb=150-ohm and Zc=225-ohm.
Very minor effect on Gain, F/B or SWR.
enlarge 0KB, 1024x819 40 YA-1713 with SOURCE at Balun Location - Gain
For optimized Zb=150-ohm and Zc=225-ohm.
enlarge 0KB, 1024x819 41 YA-1713 with SOURCE at Balun Location - SWR
For optimized Zb=150-ohm and Zc=225-ohm.
enlarge 0KB, 1024x819 42 YA-1713 with SOURCE at Balun Location - Impedance
For optimized Zb=150-ohm and Zc=225-ohm.
enlarge 0KB, 1024x819 43 YA-1713 with SOURCE at Balun Location Sweep Gap4 at 213 MHz. Initially tried Zb=Zc=75-ohm.
SOURCE wire length has no effect on Gain, F/B or SWR.
enlarge 0KB, 1024x768 44 Crossover - Side View [Back of YA-1714 is now to the RIGHT.]
enlarge 0KB, 1024x819 45 YA-1713 with 3-seg SOURCE at Balun Location. Added 50-pF Capacitor across Balun via LD1 Card. Re-optimized Zb=165-ohm and Zc=255-ohm.
enlarge 0KB, 1024x819 46 YA-1713 with 3-seg SOURCE at Balun Location - Gain Added 50-pF Capacitor across Balun via LD1 Card.
Gain Loss reduced by only a few tenths of a dB.
enlarge 0KB, 1024x819 47 YA-1713 with 3-seg SOURCE at Balun Location - SWR Added 50-pF Capacitor across Balun via LD1 Card.
enlarge 0KB, 1024x819 48 YA-1713 with 3-seg SOURCE at Balun Location - Impedance Added 50-pF Capacitor across Balun via LD1 Card.
enlarge 4KB, 791x1024 52 4nec2 File: Trying to Model YA-1713d Crossover. Element#3 SOURCE with TL Card (Direct) Crossover.
enlarge 4KB, 791x1024 53 4nec2 File: Trying to Model YA-1713d Crossover. Element#3 SOURCE with TL Card (Lc=0.33m) Crossover.
enlarge 4KB, 791x1024 54 4nec2 File: Trying to Model YA-1713a Crossover. Balun SOURCE and Crossover via TL Cards.
enlarge 4KB, 791x1024 55 4nec2 File: Trying to Model YA-1713d Crossover. Detailed Balun SOURCE and Crossover via TL Card
enlarge 28KB, 791x1024 56 4nec2 File: Trying to Model YA-1713d Crossover. Balun SOURCE (3-seg) and Crossover via TL Cards. Added 50-pF Capacitor across Balun via LD1 Card. Re-optimized Zb=165-ohm and Zc=255-ohm.
enlarge 28KB, 791x1024 57 4nec2 File: Trying to Model YA-1713d Crossover. Balun SOURCE (1-seg) and Crossover via TL Cards. Added 50-pF Capacitor across Balun via LD1 Card. Re-optimized Zb=165-ohm and Zc=255-ohm.
enlarge 145KB, 1152x380 58 YA-1713 in Real Life - Top View
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